Image Processing Apparatus Preventing Pseudo Contours in High Saturation Areas

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Solution Overview

Problem

Image processing methods that uniformly manipulate pixel values of multi-resolution image data can lead to unnatural luminance changes, particularly in areas with high saturation, resulting in the occurrence of pseudo contours.

Innovation Solution

An image processing apparatus that separates image data into luminance and color components, adjusts pixel values of multi-resolution image data based on saturation values, and composites the adjusted luminance component with the color component using specific adjustment ratios to prevent pseudo contour formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pixel values of multi-resolution image data are uniformly manipulated, then intelligibility and sense of unevenness are improved, but unnatural luminance changes and pseudo contours occur in high saturation areas

Engineering Contradiction:
ImproveintelligibilityVSAvoidpseudo contour
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by differentiating the processing approach based on saturation levels. High saturation areas use one processing method (maintaining original luminance to avoid pseudo contours), while low saturation areas use another method (enhancing luminance for better intelligibility). This is achieved through saturation calculation and conditional processing that adapts to local image characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the processing parameters dynamically based on saturation values. By calculating saturation for each pixel and using it as a condition, the system adjusts whether to apply luminance manipulation, thereby preventing pseudo contours in high saturation regions while maintaining enhancement benefits in other regions.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If pixel values of multi-resolution image data are uniformly manipulated, then sense of unevenness is improved, but unnatural luminance changes occur in high saturation areas

Engineering Contradiction:
Improvesense of unevennessVSAvoidunnatural luminance change
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent makes the processing quality local by considering saturation levels. In high saturation areas, the original luminance is preserved to avoid unnatural changes, while in other areas, luminance manipulation enhances the sense of unevenness. This localized approach ensures that processing benefits are achieved without introducing artifacts.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies partial action by selectively manipulating pixel values only in regions where it is appropriate. By using saturation as a mask, the system applies luminance enhancement partially (only in low saturation areas) rather than uniformly across the entire image, thus avoiding unnatural luminance changes in high saturation regions.

Inventive Principle:
Principle #16Partial or excessive action

3Object-affected harmful factors

If saturation-based adjustment is applied, then pseudo contours are prevented, but processing complexity increases

Engineering Contradiction:
Improvepseudo contourVSAvoidprocessing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by calculating saturation values for all pixels before the actual luminance manipulation. This pre-calculation allows the subsequent processing to proceed efficiently using the saturation map as a guide, avoiding the need for complex real-time calculations during the main processing stage.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces saturation calculation as an intermediary step that mediates between the input image and the final processed output. This intermediary saturation map simplifies the decision-making process for luminance manipulation, making the overall system more manageable despite the added processing step.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3186954B1Image processing apparatus, image processing method, recording medium, and program
Publication Date: 2020.11.04 RICOH CO LTD
  • EP3186954B1 patent drawingFigure 1~2
  • EP3186954B1 patent drawingFigure 3
  • EP3186954B1 patent drawingFigure 4

AI summary

An image processing apparatus includes a color separation unit separating image data into a luminance component and a color component; a processing unit generating second image data of the luminance component by manipulating pixel values of multi-resolution image data generated from first image data of the luminance component and reconstructing the manipulated multi-resolution image data; and a composition unit compositing the second image data of the luminance component with image data of the color component. Further, the processing unit generates the second image data of the luminance component based on pixel values which are adjusted by using parameters in accordance with pixel values of the image data of the color component.